Sonic earth boring drill with elastic fluid resonator



Dec. 29, 1964 A. G. BODINE SONIC EARTH BORING DRILL WITH ELASTIC FLUID RESONATOR 3 Sheets-Sheet l INVENTOR.

ALBERT G. BODINE ATTORNEYS Filed Sept. 21. 1960 A. G. BODINE 3 Shets-Sneet 2 FlG.8

INVENTOR. ALBERT G. BODINE ATTORNEYS Dec. 29, 1964 SONIC EARTH BORING DRILL WITH ELASTIC FLUID RESONATOR Filed Sept. 21. 1960 I M I \\V\ Li, I m 5: THHIHI 2:1; T D" 6 5 6 7 SMWM Dec. 29, 1964 A. G. BODINE SONIC EARTH BORING DRILL. WITH ELASTIC FLUID RESONATOR Filed Sept. 21. 1960 IOO/ Y 1.

95' i v ezg i mm 5 Sheets-Sheet 3 INVEN TOR.

ALBERT G. BODINE ATTOR NEY-S United States Patent 3,163,240 SQNIC EARTH BGRING DREJL WlT'l-l ELASTEC FLUKE) RESONATQR Albert G. Bodine, Sherman Gales, (Ialif. (7877 Woedley Ave, Van Nuys, alif;) Filed Sept. 21, 1950, Ser. No. 57,520 16 (Iiaims. (1. 175-56) This invention relates generally to resonant acoustic generators useful as sonic wave radiation or vibration sources, and will be chiefly described herein in its application to a sonic earth boring drill.

This application is a continuation-in-part of my copending application Serial No. 19,078, filed March 31, 1960 for Oscillatory Fluid Stream Sonic Generator with Elastic Auto-Resonator, now Patent No. 3,111,931.

Sonic earth boring drills of the general class to which the invention appertains are disclosed in my prior Patent No. 2,554,005. As there typically disclosed, the sonic drill comprises an elastic column of solid elastic material,

string. The assembly behaves, in the language of acousties, as a free-free bar. That is to say, when a longitudinal standing wave is set up in the bar, the effective mid-point of the assembly stands nearly stationary, while the two half-length portions thereof alternately elastically elongate and contract, in step with one another, so 'that the bit at the lower end is vibrated against the formation to be bored. Velocity antinodes of the standing wave occur at the vibratory upper and lower ends of the assembly, and a pressure antinode occurs at the mid-point.

The mechanical oscillator used to vibrate the sonic drilling assembly typically comprises a number of unbalanced rotors, driven through suitable gear trains from a turbine, which is in turn driven by the stream of mud fluid conventionally circulated through the drill string in deep well drilling. Owing to the relatively high horsepower demanded of such devices, the small space within which they must be accommodated, and the high stress conditions under which they must operate, practical designs become inherently complicated and expensive.

A primary object of the invention is therefore the provision of an effective sonic earth boring drill which dispenses with the turbine and mechanical oscillator of my earlier sonic drilling system as disclosed in my aforesaid Patent No. 2,554,005, .and utilizes in lieu thereof a mechanically simple system in which a resonant elastically vibratory body or column of the drilling fluid is used for creating the vibration that drives the bit.

According to one present preferred embodiment of the invention, in its illustrative application to sonic drilling, a tubular housing is provided to contain a drilling fluid body or column which is resonant at the resonant oper- 3,163,240 Patented Dec. 29, 1964 pressure pulse to the liquid body, at the resonant frequency thereof, and alternately therewith is switched or ating frequency of the usual solid elastic vibratory col-- umn of the sonic drill. A fluid flow directing means is provided by which the streamof drilling mud circulated down the drill string is cyclically switched to communidiverted to by-pass the liquid body and flow on tothe bit. The resonant liquid body may be housed in a'chamber functioning in the nature of a Helmholtz resonator, or may be in the nature of a quarter wavelength column, or odd multiple thereof, or' may have part of the characteristics of a Helmholtz resonator and part of a quarter wavelength column. In all cases, the point of impingement of the mud fluid stream on the resonant liquid body is at a low impedance point thereof, such as at the neck or How passage of a Helmholtz resonator, or at the velocity anti-node end ofa" quarter wavelength liquid column. The opposite end of the liquid body is a high impedance, pressure pulse region, where pressure pulses are maximized. Such a condition prevails in the cavity of a Helmholtz resonator, andin the cavity space at the end of a quarter Wavelength column opposite to the velocity anti-node end, i.e., at the pressure antinode thereof.

The aforementioned solid elastic vibratory column is arranged with one free end thereof exposed to the pressure anti-node zone of the resonant fluid body, the opposite freeend supporting the drill bit. This column, which corresponds fully to the elastic column of my aforementioned sonic drill of my Patent No. 2,554,005, has a length such as to undergo resonant standing wave vibration at the resonant frequency of the resonant liquid body.

In operation, the resonant frequency pressure pulses occurring in the liquid body adjacent the corresponding end of the solid elastic column set up elastic waves travelling the length of the solid column with the speed of sound. By the well-known phenomena of wave reflection from the ends of the column, and interference of forwardly travelling and reflected waves, the desired longitudinal resonant standing wave is set up in the column. In this longitudinal standing wave action, the bit end of the column vibrates longitudinally, and thus vibrates the bit against the formation to be drilled.

Other forms of the invention dispense with the solid It might here be mentioned that, broadly, the elastic fluid column is generally a liquid. In sonic drilling of the earth,-it most conveniently and preferably comprises;

a body of the drilling mud conventionally used in earth drilling. It is within the scope of the invention, however, and quite feasible in certain applications, to use a resonant gaseous body.

The invention will be more fully understood from the following detailed description of a number of illustrative embodiments thereof, reference for this purpose being directed to the drawings, in which:

FIG. 1 is a longitudinal section view, partly in elevation, of a present preferred embodiment of sonic-drill in accordance with the invention;

FIG. 2 is an enlarged view of the upper end portion of FIG. 1, additional parts being shown in section;

FIG. 3 is a section takenon line 3-3;

FIG. 4 is a section taken on line 44 of FIG. 2;v

FIG. 5 is a longitudinal sectional View showing another 7 embodiment of sonic drill in accordance with the in-' vention; FIG. 6 is a section taken on line 6-6 of FIG..5; FIG. 7 is a sectional view taken on line 77 of FIG. 5; FIG. 8 is a fragmentary view showing a modification of the lower end portion of the drill of FIG. 5;

FIG. 9 is a longitudinal sectional view of another embodiment of the invention; and

FIG. is a section taken on line 10-14 of FIG. 9. Referring now to FIGS. 1 to 4 of the drawings, there is 'fragmentarily indicated at 10 the lower end portion of a 'drill stern such as is conventionally'used in rotary earth drilling, the drill stem being understood .to be supported by conventional ground surface equipment, including rotary table equipment for imparting rotation to the drill stem, as well as other equipment ordinarily employedin with its threaded box end 12r'zcoupled to the drillstem,

andflaring at 13a to full diameter,- an intermediate part 14 in the form'of a long sleeve or jacket screw coupled to the upper part as at 15, and a lower tubular coupling member 16 screw coupled, as at 15a, to sleeve or jacket 14. Coupling member 16 is firmly joined, as at ltia, to a tapered mid-section 17 of a longitudinally vibratory elastic drill column 18. This column 18, which iscomposed preferably of a good grade of alloy steel, has an upper portion 19 extending upwardly with small clearance inside sleeve 14, and a lower section 2%, of slightly larger diameter, extending downwardly and carrying attits lower end 7 an earth boring bit 21. a

The'column 18 corresponds to the elastic longitudinally upper end opens through the upper end of the rotor convibratory drill rod or column of my aforementioned Pat ent No. 2,554,005. In, operation, cyclicpressure' pulses applied to the upper end of this column cause alternating Waves of compression and tension to be transmitted along 'its length, and reflected from the lower end thereof so as-to travel back to the top, where they are again reflected, and so on. If these pressure pulses correspond to 'a 'resonant frequency of the column fora mode of longitudinal standing wave vibration, a standing wave is set up in the column with velocity anti-node (regions of the operating frequency of the system, so that the midpoint section 17 of the column becomes the location of a velocity node, and it will be seen that the column is supported through the; jacket member 14 at this velocity In general, the operating frequency may be such node. as to provide for half wavelength operation, asfjust described, or may be of double that frequency, so as to provide a full wavelength standingwave, and it 'will further be seen that any multiple of half wavelengths may be chosen. When the column 20 is undergoing resonant standing wave operation, as just described, the bit 21 at its tic resonator.

centrically therewith, so as to receive the liquid flow from the hollow drill stem above. This bore 28 extends both circumferentially of the rotor and radiallyoutward with respect thereto in the downward direction, opening through the lower end of the rotor near its periphery. Liquid passing downwardly through this bore 28, owing to the twist therein, or the circumferential directional component thereof, causes the rotor to rotate. of rotor rotation will of course depend upon the rate'of flow of circulation liquid through the system; and may be controlled by the usual circulation pump at the ground surface. The body 2'7has a substantially semi-cylindrical upwardly opening mouth 39, defined on one sideby a wall, or web 31 extending across the diameter of housing por-': tion 12, and edits other side by the semi-cylindric sur- I face of housing portion 12 to one side of web 31'. The web 31 has at the center a cylindrical cup 32 forrec'eiv ting the aforementioned bearing 26.

Mouth 30 leads downwardly to a downwardly converging body passage 33, which terminates at the bottom in a 'port 33:! continued downwardly by a conduit 34 set tightly at its upper end into the'lower portion of body 27, and which extends downwardly through housing 13, with a bend therein so as to be in a concentric position within said housing and within sleeve 14 at the level of the upper end of column 18 and below. The conduit 34 is received within a circulation passage 35 extending through column 18, and-discharges liquid into said passage 35 for eventual discharge through the bit, as indicated at 36 in FIG. 1.:

It will be seenthatthe mouth 30 leading to conduit 34 occupies substantiallyhalf of the cross-sectional area of housing portion 12, and that an open passage37 leading downwardly in housing 13 outside body 27 occupies substantially the opposite half of said'housingportion. It will also be seen that thefluid discharge end of rotor passage 2$will alternately be locatedover mouth 30 and passage 37. The fluid entering mouth 30 flows down through conduit 34 into passages 35 and column 18 and thence through the bit, as will appear.

The fluid entering passage 37 fills the housing 13 outside of body 27 and conduit 34', and provides therein an elastic fluid body or column 38, capable, when excited by properly timed pressure pulses, of functioning as an elas The eifect of the fluid column in distributor passage 28 and in the bore of the drill stem above, when the lower end of the distributor-passage is passing over passage 37, is to exert a compressive pressure pulse Y aspirator effect of fluid flowing into mouth 30. Accordlower end is vibrated against theformation, and drilling proceeds substantially as described in my aforesaid patent. Means in accordance with the invention for applying the necessary cyclic pressure pulses to the upper end of the bar through use of a resonant liquid body will next be described.

The drill stem 10 is provided with ausual mud fluid circulation bore ltia, down which mud fluid is pumped by the usual ground surface pump. Rotatably mounted in the upper end portion 12 of tubular housing 13, immediately below the lower end of drill stem 10, is a fluid flow directing means, in this case in the physical form of a distributor motor 24 for the circulation liquid received from drill stem bore 10a. This rotor'24 is of cylindrical form, and has a downwardly projecting shaft 25 received in a bearing 26 which is set into a body 27 secured, as by welding, to the inside surface of oneside of the wall of housing 13. The distributor rotor 24 has a boreZS whose ingly, the upper end of fluid column 38 is subjected to a periodic pressure pulse, at a frequency determined by the rate of rotation of the distributor rotor, and in turn by the rate at which fluid is pumped down the drill stem from the circulation pump at the ground surface. Thedistributor rotor frequency ismade such as to resonate the elastic fluid column 38. 1

Speaking generally, the length of the apparatus is made such that the fluid column 38 has a height ap proximating f dium to be 3600 feet per'second), and taking 12 as l, for

fundamental frequency operation, the above expression The rate A waveleads to a fluid column 38 having a heightof 9 feet A Wavelength). For values of 11 equal to 2, 3, etc. (harmonic frequencies), the column heights are wavelength, wavelength, etc. Actually, owing to the constriction of the fluid column 38 at the top, in the region of passage 27, as provided in the specific embodiment of FIGS. 1-4, the column height for fundamental frequency operation is somewhat under 9 feet, owing to the fact that the reduced neck portion 37 of the fluid space in combination with the larger cross sectional area below imparts a degree of lumped constant behavior to the oscillating fluid body, as distinguished from pure dis tributed constant behavior such as is experienced with a fluid column of uniform cross section entirely along its length. The latter type of column (constants of mass and elasticity distributed uniformly therealong) experi- 6 the column 18 necessary for the desired longitudinal standing wave to be set up therein, as hereinabove ex plained. It will be understood that the column 18 is made of such length as to have a resonant frequency. for the desired mode of standing Wave vibration thereof which corresponds to the resonant frequency of the liquid column 38 for its mode of resonant oscillation. And, of course, the rotor 24 is driven at a rate of rotation corresponding to this resonant frequency. vUnder such conditions, pressure pulsatons of substantial magnitude are developed in the fluid body 38 adjacent the upper ences peak resonance when precisely one quarter wavelength long for the exciting frequency, and oscillates in a longitudinal standing wave mode, with a velocity antinode at one extremity and a pressure antinode at the other. Thiswould be an idealized distributed constant quarter wave system. When such a system is modified by constricting its cross section at one end, as in FIGS. 1 and 2, and assuming fundamental frequency excitation, behavior is modified to be more like that of a Helmholtz resonator, where a velocity variation region occurs within the restricted end portion or neck, and a pressure variation zone occurs Within the larger cross sectional portion or cavity below. A Helmholtz resonator is of course a lumped constant device, the oscillating fluid mass in the neck acting as a mass, and the fluid body in the cavity as a spring. The resonant frequency depends upon the sizes and proportions of these two parts of the resonator. When, as in FIGS. 1 and 2, the chamber is quite elongated, 'there results a hybrid resonator having partly the character of an ideal Helmholtz resonator and partly the character of a quarter wavelength column. In such case, the over-all length of the resonator is somewhat shorter than quarter wavelength for fundamental frequency operation, and to this extent, behavior is modified from that predicted by the expression for the case n:1. For harmonic frequencies, e.g., 11:2, 3, 4, etc., the constricted neck as illustrated in FIGS. 1 and 2 does not play so great a part, and the expression (Zn-1M holds quite closely. It is within the broad scope of the invention to use an idealized distributed constant, quarter wavelength fluid column (uniform cross section), an idealized Helmholtz resonator, or a cross between the two, as in FIGS. 1 and 2, which practically speaking, may be said to operate, insofar as the present invention is concerned, substantially as a quarter wavelength column, or substantially as a Helmholtz resonator. either case, there is afforded a fluid resonator, with a velocity oscillation region at the top, and a pressure antinode region adjacent the upper end of the solid elastic column 18. The elastic column acoustically couples the ressure antinode region of the fluid resonator to the bit. Assuming now fundamental frequency excitation for the apparatus of FIGS. 1-4, i.e., a body or column 38 of fluid whose fundamental frequency coincides with the frequency of revolution of the distributor rotor 24, one compressive pressure pulse is exerted on the upper end of the fluid body or column 38 per cycle, causing the latter to resonate. The upper end of the column 38 becomes a velocity oscillation region, and the lower end of the column, adjacent the upper end of solid elastic column 18, becomes a pressure oscillation region. The pressure oscillations thus occurring adjacent the upper end of column 18 induce the waves of elastic stress in end of the'resonant column 18, and the latter is thereby set into resonant standing wave vibrationat substantial amplitude. The lower end of the column 18, and the bit 21 attached thereto, then undergo a vibratory action characterized by great force acting through a. displacement distance ofthe order of .to inch. Such vibratory action against the formation engaged by the bit causes the formation to give way rapidly by the method of fatigue failure.

The usefulness of the large and massive solid elastic resonant column 18 interposed between the liquid body resonator and the bit resides primarily in a very desirable energy storage property contr'ibuited to the sonic drilling system by this component. This energystored within v the column 18 is alternately in theform ofvkinetic and potential energy, and only a small fraction of the energy stored per cycle is utilized per cycle by the bit working on the formation. The system thus works at high Q (a figure of merit of vibratory systems denoting the property in question), and a large flywheel eifect and corresponding stability is thereby attained.

It will be seen that there has been provided a high:

performance sonic drill, of great mechanical simplicity, with all the advantages attendant thereupon.

Reference is nextdirected to the embodiment of FIGS.

5 to 7, which is similar in many respects to that of FIGS.

1 to 4, but eliminates the solid resonant elastic column, the bit being acoustically coupled directly to the fluid body resonator. The invention in this form does not have the energy storing advantage of the first described 43 which flares as at 44 to a larger diameter portion 45.

This larger diameter portion 45 extends downwardly some distance to the location of the bit 46. The shank 47 of the bit is received within the lower end of housing portion 45 and arranged for longitudinal reciprocation therein, but keyed against rotation relative thereto, as by the splined connection designated-at 48. Set into bit shank 47, around its circulation passage 4?, is an upstanding sleeve Sll, and threaded on the upper end of the latter is a ring 51 which, while the bit is being lowered into the drill hole, engages and is supported by studs 52 set into theside of housing portion 45. This provision is 55 rotatably mounted in bearing provisions set into body 56 secured to the inside surface of one side of the wall.

housing 43, all in the manner of the first described embodirnent. Rotor 54 has a bore 58 for circulation fluid, concentric at its upper end with the liquid passage through the drill stem, and leading circumferentially and radially 61 and the semi-cylindric surface of housing portion'42 to one side ofsaid web, and this web 61 has atthe center.

a cylindrical cup 52 to receive the bearing for shaft 55;

Mouth 60 leads downwardly. to downwardly converging body passage 64, which terminates at the bottom in a port64a Continued downwardly by a conduit 65 set tightly at itsiupper end into the lower portion of body 56, with a bend therein so as to be in a concentric position within said housing for the greater partof its length. T his conduit is received within ring 51 and sleeve 50, and discharges'mud fluid into bit passage 49, 'all as clearly shown in-FIG. 5.

It will be seen that the mouth 60 leading to conduit 65 occupies substantialy. half of the cross-sectional area of housing portion 42, and that an open passage 66 leading downwardly in housing 43 outside body 56 occupies substantially the oppoiste side of said housing portion. It

FIGS. 9 and showa modification of theinvention,

using a modified means for switching the circulation fluid between the two alternate paths.

A tubular member 80 with a fluid flow passage 81 therethrough has at one end internal threads 82. for coupling of an intake conduit leading from a fluid pump (not shown). Beyond threads-82, the pasage S1 is constricted to form a nozzle '83,,and, as shown, the passage 81 continues on past nozzle 83 with uniform diameter at 84, and with a final flare 85 to the end of member 80. At this pend of the member 80 there is joined thereto,.as by screw threads 86, a relatively long, downwardly reaching sleeve 87. The lower extremity of this sleeve 87 has an internal shoulder 88 supporting, by a shrink fit, the mid-point of a relatively long tubular elastic bar or column 90 composed of a, solid material such as steel. Screwed into'the lower end of column 90 isthe shank of a bit B.

will also be seen that the fluid discharge. end of rotor passage 58 will alternately be located over mouth 66 and passage 66. The fluid entering mouthed flows downward via conduit to the bit, and is discharged through bit passages 52. I

The rnud fluid entering passage 66 fills the housing 4 3 outside body 56 and conduit 65; down to the level of the upper end of the bit, and. provides themud fluid column therein. The fluid slowly leaks out at the bottom between splines 43 and between conduit 65 and sleeve 59, and in operation, passage 66 accepts only 'suflicient .fluid from the distributor to replenish or compensate for this leakage flow. Assuming, therefore, a constantly filled housing 43, the effect when the lower end of the distributor passage is over passage 66, is to exert a compressive pressure pulseon the upper end of column 7i). While the distributor is discharging directly to mouth 60, the pressure on the upper'end of column 70 is' relieved. Accordingly, the upper end of fluidcolumn 70 is subjected to a periodic pressure pulse, at a frequency determined by the rate of rotation of the distributor, and in turnby resonator are withinthe scope of the invention.

The fluid space 91 inside member beyond or below the flare of nozzle 83 and inside sleeve 87 to the end of column 99 is shaped and dimensioned in accordance with resonator principles discussed hereinabove in connection with FIGS. 1 and 2, such that the elastic fluid body in said space behaves as a resonator when excited at a resonant frequency thereof. As in the case of FIGS. 1 and 2, this resonator maypartake of the character of both quarter wavelength columns and Helmholtz resonators, it being seen that the upper portion 91a of the fluid space 91 is somewhat restricted. Of course, as in the case of FIGS..1 and 2, a true or idealized quarter wavelength columnas well] as an idealized Helmholtz In all cases, assuming excitation of the fluid body in space 91 by a periodic pressure pulse at its resonance frequency applied at its upper end, the fluid body is set into elastic oscillation, with a velocity oscillation region at'its upper, end, as indicated by the double-headed arrow a, and a pressure oscillation region adjacent the end of elastic the rate at which the rnudfluid is-pumped down the drill stem from thecirculation pump at the ground surface. a V v The fluid body or column 70 is proportioned and dimensioned in accordance with principles discussed in connection with FIGS. 1 and 2 to be-resonant at. a' predetermined frequency, so as to afford a velocity oscillation region-at the top, and a pressure oscillation region at the bottom, adjacent the vibratory. bit, when the disance such as is requisite to the sonic drilling process.

The splined' connection at 4% between the bit and housing enable vibrationbf the bit relative to the housing,

and also causes rotation of the bit when the drill stem an'd thefihousing are rotated; There is thus provided a compact,,light weight, sonic drill, of great'me'chanical simplicity, yet capable of high vibratory force application to the'formation to be drilled.

- FIG. 8 shows a modification of thelower en'd portion of the drill of FIGS. 5-7, according to which the bit shank is mounted tightly within the lower portion of the tubular housing, here designated by numeral 45a,with

the collar wand studs 52 of FIG. 5 omitted; In this case, the housingelastically elongates and contracts'in step with the fluid column 76, eliminating the necessity for the'splined connections betweenthe bit shank. and

housing.

column 94). The column 90, as in the embodiment of FIGS. 1-4, has a'length such as to beresonant for a mode of longitudinal standing wave vibration at a frequency.

preferably coinciding closely to the resonant frequency of the fluid bodyin space 91, and thus is set into such vibration by the pressure variation cycle occurring in the fluid body adjacent its upper end.

It wil-l'be noted that the elastic fluid .medium of the system is constantly present in the chamber 91. Chamber 91 is in effect the primary resonator, and bar 90 is the secondary or coupled resonator. It is possible however to so dimension the apparatus that resonance does not occur, as described above, simultaneously in both elements inland-5 d at the same frequency. In this latter case only one element resonates. It is usually preferable to have the double simultaneous resonator combination. I

A fluid conduit 92 has a portion 93 extending through the bore of tubular bar 90 with small annular clearance;

therewithin, and has a flattened or semi-cylindric portion 94 received within passage portion 84 and deflected so as to lie adjacent one surface thereof, being secured to the wall surface of bore 84 by welding or brazing, as'indicated at 95. Conduit92 has a narrow mouth 96 facing upstream, and located just beyond nozzle 83. r The opposite through the flow path space or passage 91a, outside of' and to one side of the portion 94 of conduit 92, or into the conduit portion 94-. As will be shown, properly applied lateral pressure pulses periodically switch thefluid stream between these two paths. For this purpose, longitudinal bores 99 and 109 are drilled through member 30 to one side ofv fluid passage 81 for the principal length of the latter but opening through the flared portion V thereof. The forward ends of these bores are closed by means of plugs 101. The bores 99 and lot) intersect transverse bores 192 and 193 drilled inwardly into communication with passage 81 in the region of the nozzle constriction at 83. The outer ends of these bores 102 and 103 are also closed by means of plugs 104, and their inner ends terminate in orifices 102a and 193a communicating with passage 81. Scoop type port tubes 107 and 108 are set into the flared walls 95, so as to communicate with bores 99 and 180, respectively, and the scooped ends of these port tubes are positioned in the fluid flow stream paths outside and inside the conduit 92 respectively, both facing upstream.

The fluid streamissu-ing from nozzle 83 can be deflected by application of pressure pulses thereto via one of the other of orifices 102a and 163 to deflect to one side or the other, so as to flow into resonator passage.

910', or into mouth 96 leading into and through conduit 92. Basically, the fluid stream deflects away from a source of lateral fluid pressure.

Assume now that the fluid stream is initially directed so as to wholly, or partially, enter the passage 91a. The fluid body contained within chamber 91 (inclusive of the passage 91a), is thereby sufiiciently excited as to be set into a degree of elastic oscillation at the natural resonant frequency of chamber 91. A region of fluid oscillation is created in passage space 91a, as indicated by the double-headed arrow. correspondingly, a region of pressure oscillation is created at the bottom of chamber 91, adjacent the end 110 of bar 99. Again assuming fluid flow inwardly into the passage 91a, apart of this fluid is intercepted by port tube 107, and a corresponding pres-.

sure pulse is transmitted via bores 99 and 102 and orifice 102:; to impinge laterally on the main fluid stream, which is at that time sweeping the surface containing the orifice 102a. Thereby, the main fluid stream is deflected away from orifice 192a, and over into position to enter the'mouth 96 of conduit 94, The return passage constituted by port tube 107, bore 99, bore 102 and orifice 192a is designed, however, as by adjustmentof its length and/ or cross section in relation to the density of the fluid,

to have an acoustic impedance, for the operating frequency, such as to introduce a predetermined time delay of a duration such that the lateral pressure pulse at 16 2:: becomes effective to deflect the fluid stream in a proper phase relation with the oscillation cycle of the fluid body in resonator chamber 91 to preserve and augment that cycle. This time delay is thus adjusted to afford a fully developed pressure rise within the resonator chamber 91 prior to deflection of the stream into the mouth 96 of conduit 94. In other words, a time'delay is simply provided such as to afford time for completion of the oscillation half cycle during which fluid flows in'to chamber 91.

At the end of the time delay intervals, the pressure pulse at orifice 102a acts to shift the fluid stream over so as to enter conduit 92. The fluid pressure in the lower region of chamber 91 then falls, and fluid flow in neck or passage region 91:: is in the reverse direction, i.e., out- Wardly of the neck regions of the resonator. ward flow is aided'by the aspirating effect of the fluid stream going into conduit 92. V

The fluid entering conduit 92 is discharged from the opposite end thereof. A small part of this fluid flow impinges on port tube 198, and a pressure pulse is trans mitted via bores 100 and 103 and orifice 193a so as to create a lateral pressure pulse against the fluid stream in its last described position. Again, fluid port 1&8 and bores 100 and 103 are designed with an acoustic impedance affording time delay. 'W'hen, however, the pressure pulse appears at the exit orifice 183a, the fluid stream is deflected back to its initial direction, soas to flow again into passage 91a. The time delay introduced by the last mentioned return passage is such that the last mentioned switchover of the fluid stream occurs in step This outwith fluid flow inithe forward. direction in the region 9111,} in accordance with the oscillating flow condition set up] tic art, it being only necessary to point out that the time resonant frequency of the fluid body resonator.

delays introduced are to be such as to effect back andforth switchover of the fluid stream at halt-cycle intervals of the resonant frequency of the resonator. It is important to note that, with a system employing an acoustic resonator such as chamber 91, the acoustic pulses transmitted through the pulse return passageways need be only elastic pulses, andthus there need be no net flow therethrough. It might also be mentioned that the pres.- sure pulse's transmitted back and applied to the fluid stream at 192a and 10:36: are substantially of the same wave form as the resonator cycle. 7

Pressure pulsations are thus set up in resonator chamber 91 adjacent and against the end of bar at the These pressure pulses applied against the end of bar 90 set said bar into longitudinal standing wave vibration at substantial amplitude, and its forward extremity 112 and the bit B coupled thereto are set into powerful longitudinal vibrations. i It will be understoodthat while the invention has been disclosed as a sonic drill, and has its principal present application as a drill, it has other applications, and work-,

ing tools other than bits may be used thereon. Moreover, by omission of the bit, or hit blades, the vibratory output member becomes a high energy source of sound wave radiation into an elastic medium in contact there with or coupled thereto.

It will be understood that the drawings and descriptions are merely illustrative of the invention, and that 1 various changes in design, structure and arrangement may be-made' without departing from the spirit and scope of the invention and of the broader of the appended claims.

I claim: e

-I. In a sonic drilling system having a drill stem with a circulationpassage therethrough and means for circulating drilling fluid down said stem, a drilling apparatus comprising: a tubular vertically disposed housing including means for coupling said housing to said drill stem, said housing forming a fluid chamber having an entrance passage communicable with the circulation passage of said stem and adapted to receive circulation liquid therefrom, a vibratory means having a surface exposed within the lower region of said chamber and forming a boundary thereof, bit means on said vibratory means, means forming a byapassing fluid passage having an entrance mouth alongside said fluid chamber entrance, passage, said bypassing passage extending from said mouth downwardly in said housing and through said vibratory means to discharge externally at said" bit means, and movable body means operable for cyclically deflecting the fluid stream from said drill stem between said entrancepas sage to said chamber and said by-passing fluid passage at a resonant frequency of the fluid body contained in said fluid chamber for a mode. of elastic oscillation of said fluid body.

2. The subject matter of claim 1, wherein said'swi'tching means comprises a rotor rotatably mounted in said housing above said entrance passage to said chamber and said entrance mouth of said by-passing fluid passage, said rotor having a fluid distributor passage extending there-' through opening at the top to receive circulation fluid from said drill stern and opening eccentrically of the rotor at'the bottomthereof to communicate alternately, in successive positions of rotation thereof, with said entrance passage to said chamber and said entrance mouth of saidby-passing passage, said rotor including fluid drive means for rotation in response to flow of said circulation fluid;

3. The subject matter of claim 2 wherein cumferentially \ofsaid rotor whereby to impart rotation to said rotor.

4. In a sonic drilling system having a drill stem with a circulation passage therethrough arndmeansfor circulating drilling fluid down said stem, a drilling apparatus comprising: a' tubular vertically'disposed housing including means for coupling said housing to said drill stem, said housing forming a fluid chamber having an entrance passage communicable with the circulation passage of said stem and adapted to receive circulationliquid' therefrom, a vibratory bit. having a bit shank received in the lower end of said housing and an end surface on said bit shank exposed Within the lower region of said chamber and forming. aboundary thereof, means forming a by-passing fluid passage having an entrance mouth alongside said fluid chamber -entrance passage, said by-passing passage extending from said mouth downwardly in said housing and through said vibratory bit,'and movable body means operable for cyclically deflecting the fluid stream fromsaid drill stem between said entrance passage to said chamber and said by-passing fluid passage at a resonant frequency of'the fluidbody contained in said fluid chamber for a mode of elastic oscillation of said fluid body.

5. The subject matter of claim 4 including intermeshing splines on said bit shank and the lower end portion of said tubular housing.

6. The subject matter of claim 4, wherein said bit shank is mounted on the lowerend of said tubular housing, and wherein said tubular housing is capable of elastic elongation and contraction to accommodate bit vibration.

7. The subject matter of claim 4,'wh erein said switching means comprises a rotor rotatably mounted in said housing above said entrance passage to said chamber and said entrance mouth of'said lay-passing fluid passage, said rotor having a fluid distributor passage extending there- 1 through opening at the top to receive circulation fluid from, said drill stem and opening eccentrically of the rotor at the bottom thereof to communicate alternately, in successive positions of rotation thereof, withsaid entrance passage to said chamber and said entrance mouth of said by-passing passage, said rotor including fluid drive means for rotation in response to flow of said circulation fluid.

8. In a sonic drilling system having a drill stem with a circulation passage therethrough and means for circulating drilling fluid down said stem, a drilling apparatus comprising: a tubular vertically disposed housing including means for coupling said housing to said drill stem, a solid elastically vibratory column joined atfan intermediate point thereof to the lower. end portion of said tubular housing, and having a portion extending upwardly with- .in said housing above said intermediate point and a por-.

tion extending downwardly therebelow, a bit on the lower end of said column, said housing and said upwardly extending portion of said column forming afluid chamber having an entrance passage communicable with the circu- 7 said fluid dis: =tributor passage in said rotor has an extent directed cirby-passing passage, said rotor'including fluid drive means at the bottom thereof to communicate alternately, in suc-' cessive positions of rotation thereof, with said entrance passage to said chamber andsaid entrance mouth of said for rotation in response to flow of said circulation fluid.

11. In a sonic drill, the combination: a chamber constructed and arranged so as to contain an elastic fluid body sure fluid coupled to said chamber, fluid flow directing 5 having a resonant oscillation frequency and separated oscillation regions, one comprising a flow passage of predominantly velocity. oscillation and one comprising a cavity of predominantly pressure oscillation, a source of presmeans operable at said resonant frequency for intermittently directing fluid from said source of pressure fluid to said velocity oscillation region of said fluid body, whereby to subject said velocity oscillation region of said fluid body to intermittent fluid pulses, and a vibratory bit acoustically coupled to said pressure oscillation region of said fluid g,

body and arranged so as to vibrate in response thereto.

12. In a sonic drill, the combination of: a chamber constructed and arranged so as to contain an elastic fluidbody having a resonant oscillation frequency and separated oscillation regions, one comprising a flow passage of predominantly velocity oscillation and onecomprising a cavity of predominantlyrpressure oscillation, a source of pressure. fluid coupled to said chamber, fluid flow directing means operable at said resonant frequency for intermittentlydirecting fluid from said source of pressure fluid to said velocity oscillation region of said fluid body, whereby to subject said velocity oscillation region of said fluid body to intermittent fluidpulses, a solid longitudinally elastically vibratory column mounted'with its endportions w free for longitudinal vibration and with one end subjected 1. to the pressure oscillations occurring in said pressure 05- cillation region of said fluid body, and a bit on the opposite end of said column. I

13. The subject matter of claim 12, wherein said solid elastic column has a length equal to any multiple, includlation passageof said drill stern and adaptedto receive v circulation liquid therefrom,-means forming a by-passing fluid passage having an entrancemouth alongside said fluid chamber entrance passage, said by-passing passage extending downwardly in said housing and through said column and bit, and movable body means operable for cyclically deflecting the fluid stream from said drill stern between said entrance passage to said chamber and said by-passing fluid passage at a resonant frequency of the fluid body contained in said fluid chamber for a mode of elastic oscillation of said fluid body. g

9. The subject matter of claim 8, wherein said solid elastically vibratory column has a length such as to be resonant fora longitudinal standing wave mode of opera-tion at said resonant frequency of said fluid body, and so as to a have velocity antinodes at its two ends and a velocity node located'at an intermediate point thereof, and wherein said i ing unity, of a half-wavelength in the column for a sound wave having a frequency near the resonant oscillation frequency of said fluid body.

14. The subject matter of claim 11, wherein said vibratory bit has a shank provided with an upper end posi tioned in communication with said pressure oscillation region of said chamber arid subjectedt'o the pressure oscillations occurring therein.

15. The subject matter of claim 11, including means forming a fluid discharge passageway by-passing said chamber, and wherein said fluid directing means comprises a rotary fluid distributor for receiving a fluid stream from said source and directing-and switching said stream to flow alternately to said velocityoscillation region of said fluid body and into said fluid discharge passageway.

a 16. The subject matter of claim 11, wherein said source comprises a nozzle adapted to deliver a fluid stream which is laterally deflectable between two paths in response to pressure pulses oppositely laterally applied thereto, and wherein the velocity oscillation region of said chamber includes a throat adapted to receive said stream of fluid when deflected into one of said paths, and comprising also 7 means forming a fluid by-pass passageway leading around said chamber to a pointiofldischarge, said passageway havingan entrance opening disposed alongside said throat of said chamber and adapted to receive said stream of fluid when the latter is deflected intothe otherof said paths, saidfluid flow directing means including a fluid 13 flow responsive means in the velocity oscillation region of said chamber for developing a pressure pulse in response to fluid flow therepast and applying it laterally to said stream in a direction to deflect it away from the throat of said chamber and into said by-pass passageway, and a fluid flow responsive means in said by-pass passageway for developing a pressure pulse in response to fluid flow therepast and applying it laterally'to said stream in a direction to deflect it away from said by-pass passageway and into the throat of said chamber.

References Cited in the file of this patent UNITED STATES PATENTS Boucher Sept. 6, 1960 

11. IN A SONIC DRILL, THE COMBINATION: A CHAMBER CONSTRUCTED AND ARRANGED SO AS TO CONTAIN AN ELASTIC FLUID BODY HAVING A RESONANT OSCILLATION FREQUENCY AND SEPARATED OSCILLATION REGIONS, ONE COMPRISING A FLOW PASSAGE OF PREDOMINANTLY VELOCITY OSCILLATION AND ONE COMPRISING A CAVITY OF PREDOMINANTLY PRESSURE OSCILLATION, A SOURCE OF PRESSURE FLUID COUPLED TO SAID CHAMBER, FLUID FLOW DIRECTING MEANS OPERABLE AT SAID RESONANT FREQUENCY FOR INTERMITTENTLY DIRECTING FLUID FROM SAID SOURCE OF PRESSURE FLUID TO SAID VELOCITY OSCILLATION REGION OF SAID FLUID BODY, WHEREBY TO SUBJECT SAID VELOCITY OSCILLATION REGION OF SAID FLUID BODY TO INTERMITTENT FLUID PULSES, AND A VIBRATORY BIT ACOUSTICALLY COUPLED TO SAID PRESSURE OSCILLATION REGION OF SAID FLUID BODY AND ARRANGED SO AS TO VIBRATE IN RESPONSE THERETO. 